Multibody Simulation of Derailment Risk in Railway Switches Due to Switch Rail Irregularities Caused by Foreign Objects

Paper i proceeding, 2025

Railway switches play a crucial role in ensuring smooth railway operations. Efforts to enhance switch safety standards led to the implementation of so-called TKK sensors in Sweden. These monitor the gap between switch rail and stock rail as a complement to the switch and locking devices. However, these devices are susceptible to faults, leading to increased maintenance and operational expenses. This study was therefore initiated to assess the utility of these devices in derailment prevention. To assess the risk of derailment caused by foreign objects getting stuck between the switch and stock rail, multibody simulation (MBS) evaluations are performed. A structural track model is built where the switch panel and adjacent track is modelled using Simpack’s non-linear flextrack module. Results from the simulation indicate that the train will not derail when the foreign object is modelled with a failure criterion resembling crushing of ballast stones. Consequently, the inclusion of additional TKK devices does not significantly improve the intended safety levels for the investigated simulation cases. Further investigations into ballast stone properties, different switch designs and traffic situations are needed to draw firm conclusions.